One of conventional semiconductor superlattices is described on pages 635 to 638 of "Appl. Phys. Lett. 41(7), Oct. 1, 1982". The semiconductor superlattice is of a quantum well submicron wire structure which comprises linear quantum well regions, and a quantum barrier region surrounding the quantum well regions.
In the semiconductor superlattice, electrons and holes which are confined in the quantum well regions are on the quasi-one dimensional condition. For the reason, the semiconductor superlattice is applicable to a semiconductor laser with a high performance.
Further, a semiconductor laser having an active layer in which quantum well boxes are provided to increase a quantum confinement is proposed in "Jpn. Appl. Phys. 26, (1987) L225".
According to the quantum well submicron wire structure or quantum well box structure, however, a semiconductor laser oscillation can not be obtained by the current injection thereinto for the reason why electrons and holes can not be injected into the quantum well regions effectively.